<!DOCTYPE html>
<html lang="en">
<head>
    <meta charset="UTF-8">
    <title>元素节点操作</title>
    <script type="text/javascript"src="../js/jquery-3.3.1.js"></script>
    <script type="text/javascript">
        $(document).ready(function () {
            var  $node=$("<li>橘子</li>");
            $("ul").append($node);
        })
    </script>
</head>
<body>
      <ul>
          <li>香蕉</li>
          <li>苹果</li>
      </ul>
</body>
</html>